The Surprising Thing Behind Your Weight Gain

So here's yet another reason to hate smoky bars (if your city still allows them): A new study reveals that being around cigarette smoke could have yet another nasty byproduct: weight gain.

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Many people believe cigarettes can suppress your appetite, but a new animal study in the American Journal of Physiology: Endocrinology and Metabolism has revealed that cigarette smoke could actually change the way our cells respond to insulin, causing us to gain weight.

Researchers at Brigham Young University worked with four groups of mice. One was a control group, one was exposed to secondhand smoke, one was given a high-fat, high-sugar diet, and one was both exposed to smoke and the bad diet, which was chosen because smokers often tend to engage in unhealthy eating habits. Of the four groups, the mice with the smoke and the fatty, sugary diet gained the most weight—importantly, more weight than the mice just eating the bad diet. The scientists then worked to identify why this was the case at the cellular level. Turns out that the smoke caused ceramide, a lipid molecule that maintains cell structure, to disrupt normal cell function. One of those normal functions? Responding properly to insulin. That means the smoke changes metabolic function at the cellular level, they concluded, which is likely what was behind the weight gain.

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The study may have been on mice, but there could be implications for humans, too. Previous research has shown a connection between smoking and insulin resistance, but the researchers have now been able to pinpoint the cellular explanation, which brings them one step closer to finding a way to stop it. "In the end, the results suggest a potential use for anti-ceramide therapies in preventing at least some of the metabolic consequences of smoke exposure," wrote the researchers in the study. 

Nonetheless, it's important to remember that this study was an animal study, which means further (human) studies are obviously needed to determine if these findings could translate across species. What you can use them for is yet another reason to steer clear of cigarette smoke—the researchers pointed out that half of all Americans are exposed to secondhand smoke at least once a day. Yes, still!

So you now have our permission to be even more of a total buzz kill around smoker friends. Keep it out of your car, out of your living room, and away from your fragile lungs (and waistline).

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